Expansion bolt



L. R. ZIFFERER I EXPANSION BOLT Filed June l5, 1928 y pander per se; and

shield with the Patented Aug. 5, 1930 UNITED STATES,

LOTHAR R. ZIFFERER, OF GOLMBIA, PENSYLVANIA i EXPANSION BOLT Application led June 15,

`This invention relates to an expansion yholt having a shield with two pivoted sections beinthe form of a'- tween which is an expander wedge nut; Y p

The present improvements are directed to means which retains the expander assembled with the shield prior to expansion; which promotes an expansion of the shield prior to securing of the work in place; and which yprotects the expander prior to advance thereinto of the bolt which serves to draw the wedge nut longitudinally ofthe shield,

An exempliiicationY of my invention is set forth in the accompanying drawing in the manner following:

Figure l is a view in elevation of the shield as it appears when first introduced into the holeprepared for its reception in a body of masonry, concrete, or the like;

Fig. 2 is a similar view showingthe shield advanced longitudinally to nal position within the hole, the shield being initially expanded during this movement;

Fig. 3 is a similar view of the shield sections as they appear when further ex-pandedl upon application of the' work to the expander;

Fig. lisa longitudinal sectionthrough the Y parts positioned about as showninFig. 3;v

F ig. 5 is a longitudinal section taken' on line 5-5of Fig. 4.;

Fig. 6 isa view in perspective ofthe ex Fig 7 isy a view in perspective of the clip forming the expander retaining means;

Ina body A Ofconorete, masonry, or the like, ahole B is provided for the reception of the present expansion bolt which comprises 4.0 a pair of shield sectionsC and C substantially alike; One of these sections may be equipped with a pair of lugs 8 whichA overlaps the other section. whereon Yare provided llaterally exv y Y A y y Vnear their fi'nner ends are kcut-r awayy at 19 'to tendingv pins. 9 extending* through aperturesl in the lugswhereby, to establish a pivotal connection between the two sections of the shield. Thisconnection, it will be noted, is l.near thelv outer shield end so as to permit theinner ends of the shield sectionst'o Vswing apartfreely; a limited distance 'in response to forces' of engaging bolt .i

1928, SerialNo. 285,734.

expansion produced by advance of a wedge nut D. This free swinging movement is arrested when Vthe outer ends ofthe shield sections come together, as shown in Fig. 2; The outerv surfaces of the two shield sections may" be provided with ribs 10 and 11 disposed circumferentiallyand longitudinally so as to resist longitudinal and rotary movementsl ofV the expansion when lthe shield sections lare engaged with the wall surfaces surrounding the hole B.

vThe interior of each shieldsection is provided'l with` a concave inclined surface- 12:

against which the expanderexerts an increasr ing pressure as it is advanced: toward the outer end of the expansion. Y The expander, as bestshownin'Fig. 6, is in the general form of a truncated cone havingan elliptical cross section whereby to provide tapering-sides 13 'adapted-'to engage with the inclined 'surfaces 12-upon the interior of the shield sections. For the major portion'of its length lthe expander is `split by the provision of shouldered slots 14 which are arrangedoppositely in the plane of its-shorter axis. Each of these slots proceeds from its innerl larger end close to' the outer smaller end,vand may terminatein yan enlargement 50` of such character as to l'facilitate' bending of the twosplitnut sections in response to sucientfforce-which is` developed for this purpose. vTheouter 'smaller endY of thenut is continuous so as to fhave 'thefformy of a Vcollar 16; The nut is K `Vthreaded interiorly at 17;.to cooperate with.V

the screw .threads ofa bolt E adapted to'pass throughthe work F so as to present the bolt headl .18 inY engagement therewith. lThe threaded hole which isy extendedrlengthwise ofthejnut ispreferably tapered slightly toward its inner end'so ,as to oder anv increasing iresistance'to the passage therethrough 'of the threaded bolt. o l. The meeting edges of the `shiel'dsecti'onsl provide space`s 20fclosed at its'bottom by thev projection of two pairs ofllugs '21 which extend from theshield sections,y as shown. Dis- :posed within these spaces andsupported i uponthe vtwo ipairsv ofprojecting lugs Aare llia'nges 22' which 'are outturned fror'n'two ver-'J 10U;

tical arms 23 of a clip G (see Fig. 7) having a bottom plate 24. During handling of the expansion, and prior to operation thereof, this clip is disposed as shown in Fig. 1 with its bottom plate 24 underlying the expander to retain the same assembled between the shield sections. The clip arms are initially disposed with the slots 14 of the split expander, and close to the shouldered portions of such slots so` as to be correctly positioned tially protruded beyondthe inner end of the golfshield, as shown Vin Fig. l, thereby causing the outer shield end to protrude from the hole for a slight distance.y ByV a blow from a hammer or other implement, the shieldmay be driven into the hole to the final longituzdinalposition which is indicated in Fig. 2.

in this operation,itheexpander and clip are forced further into the shield wherebyto produce an initial expansion of its two sections, butthe` condition of the expanderV itself remains unchanged due to the interposition of the clip arms which prevent the split sections` of the nut from being forced toward one another. l/Vhile in this position, the shield will remain stationary during application of the bolt E which passes through the work and into the expander preliminary to further separation of the Yshield sections.

Itis to be noted that up to this point the clip bottom 24 remains tight against theV lower end of the expander so as to prevent the entrance thereinto of anydirt or grit which otherwise might foul the nut threads and interfere with subsequent operations. The bolt is adapted to enter freely into the continuous upper endof the expander which remains undistorted, as above noted. As the bolt is screwed further into the expander,

it encounters an increasing yfriction owing. tothe slight taper of the threaded split sec-r, ltions of the nut. Eventually the clip arms will be crushed or crowded away from between the split sections of the expande'r'in response vto an increase in the wedge force developed. By the application of a sufficient torsional forcev the bolt will beA required to f lpass through the expander as far as necessary, thereby drawing the same outwardly when theybolthead 18 engages with the work.

' The final position of the expander may be well towardv theoouter end of the shield sec.-

tions, depending uponthe degree of expanv y o o ports, the ylength of the Vclip being yless than sion which-isrequired for .producing a secureanchorage.`l

The present expansion'boltis advanta-f` geous on `account of theseveral features al-'f ready referred to. tis'also capable of expansion to an unusual degree. The pivoted outer end of the expansion is unaected to any considerable extent by the separation ythe tapering interior surfaces of the shield so as to prevent collapse of'its sections, there by `preserving the parts in condition'for further service when .the bolt is reintroduced. Also,`because of the friction obtaining between'thebolt and the expander, the former will notv tend to unscrew should the work'become loose for anyreason, This is of 'parp ticular advantage where the expansion is used to fasten a seatY to the floor, it beingia common faulty that vonce the seat starts toAv worl loose, thebolt will yalso tend to loosenl v its hold on the expander until finally itdisengages completely therefrom.

Iclaim: ,Y y w I, l. An expansion lbolt comprising a pairfof shield sections pivotedat their outer ends Van-d provided interiorly with surfaces which taper inwardly from the inner fend, and the ladjacent edges of which are) cut away to provide a retaining slot, a tapered expander nut movableV between the shield `sections toward the outer end thereof to produce expansion,

and a clip of less length than the 'shield sections movably retained within the slot and overlying the corresponding end of the nut to retain the same between the shield` .sec-v tions, substantially as described.

Y 2. An Vexpansion bolt comprising a pairof separable shield sections having inclinedisurfaces interiorly thereof and cutaway portions adjacent the inner ends, a wedge-shaped i expandery movable between the sections t0- wardlthe outer end thereoffor producing ex- `pansion, and a clip of less length than the `shield sections having means movably retained by the cut away portion of the shield sections and a bottom plate disposednormally beyond the inner end of the shield sections tc furnish support for the expander, whereby the latter is retained between the shield sections with the inner end of" the expander protruded pst the inner end ofthe shield, substantiallyas described.

`3. An expansion lbolt vcomprising a .separable shield sections having adjacent `their inner ends oppositepairs of lugs which .ff

co-operate to provide two supports, asheet metal clip in theform 'cfa plate with `up-V standing parallel armsfeach. having an outturnedend adapted to rest on one of the sup- :mak

shield sections and retained against displacen ment therefrom by engagement with the plate end of the clip, substantially as described.

4. An expansion bolt comprising a pair of separable shield sections, means connecting the shield sections for pivotal movement adjacent their outer ends and adapted to impose a normal limit on such swinging movement, a clip having a pair of arms receivable between the shield sections at their inner ends, a pair of lugs projecting from each shield sectionl toward the other adapted to engage with said arms to retain the clip in place, the extent of normal swinging of the shield sections being insuficient to permit demounting of the clip from the shield, and an expander in the form of a wedge retained by the clip and movable between the shield sections for separating the same, substantially as described.

5. An expansion bolt comprising two piv- I otally joined shield sections formed at their inner ends with cooperating projections providing' a stop, an expander initially disposed in part to the outside of the inner shield end and movable between the sections thereof to swing one relative to the other, and a clip 1of less length than the shield sections underlying the expander outside of the inner shield and movable between said shield sections having retaining means adapted to engage the stop at the inner shield end, substantially as described.

6. An expansion bolt comprising a split shield formed interiorly with tapered surfaces, a split expander movable between the shield sections for j producing separation thereof, and means connecting the expander to the shield and extending into the split of the expander to prevent distortion of the former during initial expansion of the latter.

In testimony whereof I have hereunto set my hand thisth day of J une, 1928.

LOTHAR R. ZIFFERER. 

